It was invented by a Japanese mathematics instructor, Tetsuya Miyamoto. His goal was to improve his students’ math and logic skills. As explained at the website:

“KenKen is a grid-based numerical puzzle that uses the basic math operations-addition, subtraction, multiplication, and division-while also challenging your logic and problem-solving skills. By altering the size of a KENKEN grid, from 3 x 3 up to 9 x 9, and employing different combinations of the math operations, five different difficulty levels can be generated, and a seemingly endless number of puzzles. In a way, KenKen is like a game of chess: The more you think ahead to your next move and consider all the possible outcomes, the better you’ll get-and the smarter you’ll become!”

When you get to the website you’ll see the puzzles of the day. If you’re unfamiliar with KenKen, click on “How To Play” on the menu at the top of the page. You’ll not only read an explanation of how to play, but you can follow a step-by-step tutorial. Then, test your skills with the daily puzzles.

Bookmark the site to return each day for the daily puzzles, or sign up (as a teacher) to receive the free newsletter and a set of KenKens will be emailed to you weekly.